The Bates method is an alternative therapy aimed at improving eyesight. Eye-care physician William Horatio Bates, M.D. (1860–1931) attributed nearly all sight problems to habitual strain of the eyes, and felt that glasses were harmful and never necessary. Bates self-published a book, Perfect Sight Without Glasses, as well as a magazine, Better Eyesight Magazine, (and earlier collaborated with Bernarr MacFadden on a correspondence course) detailing his approach to helping people relax such ""strain"", and thus, he claimed, improve their sight. His techniques centered on visualization and movement. He placed particular emphasis on imagining black letters and marks, and the movement of such. He also felt that exposing the eyes to sunlight would help alleviate the ""strain"".Despite continued anecdotal reports of successful results, including well-publicised support by Aldous Huxley, Bates' techniques have not been objectively shown to improve eyesight. His main physiological proposition—that the eyeball changes shape to maintain focus—has consistently been contradicted by observation. In 1952, optometry professor Elwin Marg wrote of Bates, ""Most of his claims and almost all of his theories have been considered false by practically all visual scientists."" Marg concluded that the Bates method owed its popularity largely to ""flashes of clear vision"" experienced by many who followed it. Such occurrences have since been explained as a contact lens-like effect of moisture on the eye, or a flattening of the lens by the ciliary muscles.The Bates method has been criticized not only because there is no good evidence it works, but also because it can have negative consequences for those who attempt to follow it: they might damage their eyes through overexposure of their eyes to sunlight, put themselves and others at risk by not wearing their corrective lenses while driving, or neglect conventional eye care, possibly allowing serious conditions to develop.